take it upon (oneself) to (do something)

take it upon (oneself) to (do something)

To decide to do something even though it is not one's responsibility. I took it upon myself to print out these information packets for the meeting since I knew the data might be confusing. The kids took it upon themselves to wash your car—I'm so proud of them for doing it without being told!
See also: take, upon
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.

take it upon oneself

Also, take on oneself. Undertake something, as in I took it upon myself to count the precise number of children in the audience, or She took it on herself to enter a convent. [Second half of 1400s]
See also: take, upon
The American Heritage® Dictionary of Idioms by Christine Ammer. Copyright © 2003, 1997 by The Christine Ammer 1992 Trust. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
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